Microbial strain data are being entered into a data bank which provides such services as: data on specific organisms and/or groups of organisms, a locator service for strains with special characteristics, identification of unknown isolates, cluster analysis definition of parameters of taxa, data management and report writing aids for research purposes, aids in quality control of tests, methods, and laboratories, and communication of data via common format. Data files of primary data on a large number of microorganisms found in the oral cavity and related types are being established. These files provide a resource for asking both ecological and epidemiological questions of interest in dental research. Programs are being developed and tested to enter, retrieve, and analyze the data in a variety of ways for epidemiological and diagnostic, taxonomic ecological, etc. uses. The long term goal is to establish a worldwide data bank at a series of cooperating centers. The system originally developed for bacteria is now being expanded to include the algae, yeasts, molds and protozoa. A series of monographs describing the expanded system is in varying stages of preparation.